Cite the scanned version of the original dicionary like this:
Bosworth, Joseph. "a-cealdian." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth. Ed. Thomas Northcote Toller. Oxford: Clarendon Press, 1898. 5.
.Add : -- Swá ðæt wearme wlacaþ ǽr hit eallunga ácealdige ita a calore per teporem reditur ad frigus, Past. 447, 6. Hé læg ácealdod on nyþeweardum limum, Hml. Th. i. 534, 10. [Acoaldest, A. R. 404. O. H. Ger. er-kaltén.]